Statistics for Psychology

Adapted from Aron, Coups, & Aron (2013). This assignment has 8 questions.Make sure all of your work is shown. Points will be taken off otherwise.

1. On a measure of artistic ability, the mean for college students in New Zealand is 150 and the standard deviation is 25. Give the z-scores for the New Zealand college students who score (a) 100, (b) 120, (c) 140, and (d) 160. Give the raw scores for persons whose z-scores on this tests are (e) -1, (f) -.8, (g) -2, and (h) 1.38.

2. A person scores 81 on a test of verbal ability and 6.4 on a test of quantitative ability. For the verbal ability test, the mean for people in general is 50 and the standard deviation is 20. For the quantitative ability test, the mean for people in general is 0 and the standard deviation is 5. Which is the person’s stronger ability: verbal or quantitative? Explain your answer to a person who has never had a course in statistics.

3. The amount of time it takes to recover physiologically from a certain kind of sudden noise is found to be normally distributed with a mean of 80 seconds and a standard deviation of 10 seconds. Using the 50%-34%-14%-2% figure, approximately what percentage of scores (on time to recover) will be (a) above 100, (b) below 100, (c) above 90, (d) below 90, (e) above 80, (f) below 80, (g) above 70, (h) below 70, (i) above 60, (j) below 60?

4. Suppose that the scores of architects on a particular creativity test are normally distributed. Using the Normal Curve Table, what percentage of architects have z-scores (a) above .10, (b) below .10, (c) above .20, (d) below .20, (e) above 1.10, (f) below 1.10, (g) above -.10, and (h) below -.10.

5. Using the example from #4 about scores of architects on a particular creativity test, what is the minimum z-score an architect can have on the creativity test to be in the (a) top 50%, (b) top 40%, (c) top 60%, (d) top 30%, and (e) top 20%.

6. Suppose that you are designing an instrument panel for a large industrial machine. The machine requires the person using it to reach 2 feet from a particular position. The reach from this position for adult women is known to have a mean of 2.8 feet with a standard deviation of 0.5. The reach for adult men is known to have a mean of 3.1 with a standard deviation of 0.6. Both women’s and men’s reach from this position is normally distributed. If this design is implemented, (a) what percentage of women will not be able to use this instrument panel? (b) What percentage of men will not be able to use this instrument panel? (c) Explain your answer to a person who has never had a course in statistics.

7. Suppose that you are going to conduct a survey of visitors to your campus. You want the survey to be as representative as possible. (a) How would you select the people to survey? (b) Why would this be your best method?

8. You are conducting a survey at a college with 800 students, 50 faculty members, and 150administrators. Each of these 1,000 individuals has a single email address listed in the online campus directory. Suppose you were to select one email address at random. What is the probability it would be (a) a student, (b) a faculty member, (c) an administrator, (d) a faculty member or administrator, and (e) anyone except an administer. (f) Explain your answer to a person who has never had a course in statistics.